1 Import data

2 Abbreviations

3 Table 1

Potato genotypes (*Solanum tuberosum* L.) used for water deficit experiment with two commercial varieties and 13 genotypes from advanced breeding population developed by the International Potato Center (CIP). Source: CIP
Number	Genotypes	Adaptability	Growing period	Heat tolerance	Dry matter (%)
G01	CIP720088 (Achirana-INTA)		Early		19
G02	CIP392797.22 (UNICA)	Lowland and highland Tropics	Medium		21
G03	CIP397077.16	Lowland tropics	Medium		20
G04	CIP398192.213	Mid elevation tropics	Medium	Tolerant	22
G05	CIP398180.612		Medium
G06	CIP398208.704	Mid elevation tropics	Medium	Tolerant	24
G07	CIP398098.119	Mid elevation tropics	Medium	Tolerant	26
G08	CIP398190.89	Mid elevation tropics	Medium	Tolerant	21
G09	CIP398192.592	Mid elevation tropics	Medium	Tolerant	21
G10	CIP398201.510	Mid elevation tropics	Medium	Tolerant	20
G11	CIP398203.244	Mid elevation tropics	Medium	Tolerant	20
G12	CIP398203.5	Mid elevation tropics	Medium	Tolerant	13
G13	CIP398208.219	Mid elevation tropics	Medium	Tolerant	22
G14	CIP398208.33	Mid elevation tropics	Medium	Tolerant	21
G15	CIP398208.620	Mid elevation tropics	Medium	Tolerant	21

4 Tables 2

Treatment comparison for 17 variables between Well-Watered (WW) and Water Deficit (WD) in 15 potato genotypes. The values for different variables are represented by the mean ± standard deviation with the significance under t-test with their respective p-values.
Variable	Water deficit	Well-Watered	p-value
Chlorophyll concentration (SPAD) at 29 dap	56.1 ± 4.9	56.7 ± 5.0	0.4
Chlorophyll concentration (SPAD) at 59 dap	47.9 ± 4.4	45.8 ± 3.7	0.002
Chlorophyll concentration (SPAD) at 76 dap	46.0 ± 5.4	41.7 ± 3.6	<0.001
Chlorophyll concentration (SPAD) at 83 dap	44.1 ± 5.9	39.7 ± 4.5	<0.001
Plant height (cm)	132 ± 15	150 ± 16	<0.001
Relative water content (%)	58 ± 6	69 ± 5	<0.001
Leaf osmotic potential (MPa)	-2.84 ± 0.30	-2.25 ± 0.29	<0.001
Leaf dry weight (g)	12.0 ± 3.7	17.3 ± 5.5	<0.001
Stem dry weight (g)	11.6 ± 9.1	14.5 ± 6.1	<0.001
Root dry weight (g)	3.67 ± 1.94	3.50 ± 1.96	0.6
Tuber dry weight (g)	24 ± 11	40 ± 19	<0.001
Tuber number (N°)	12.0 ± 6.2	12.0 ± 4.9	0.8
Total transpiration (mL)	4.52 ± 1.22	7.85 ± 2.20	<0.001
Leaf area (cm²)	2,488 ± 797	7,100 ± 2,380	<0.001
Root length (cm)	33.1 ± 6.5	32.5 ± 5.8	0.4
Total dry biomass (g)	51 ± 16	75 ± 24	<0.001
Harvest index (HI)	0.47 ± 0.16	0.53 ± 0.14	0.020
Specific leaf area (cm²g^-1)	218 ± 62	415 ± 82	<0.001
Relative chlorophyll content (RCC)	0.021 ± 0.015	0.008 ± 0.007	<0.001
Biomass water use efficiency (gL^-1)	11.32 ± 2.15	9.53 ± 1.26	<0.001
Tuber water use efficiency (gL^-1)	5.31 ± 2.03	5.09 ± 1.75	0.5

5 Figure 1

Traits measured in 15 potato genotypes under well-watered (WW) and water deficit (WD) condition. (A-B) Chlorophyll concentration. (C) Tuber dry weight. (D) Relative chlorophyll content. (E) Harvest Index. (F) Tuber Water Use Efficiency. Error bars indicate standard error (n = 5). Days after planting (dap).

6 Figure 2

Relationships among agro-morphological traits evaluated in well-watered (WW) and water deficit (WD) treatments based on Pearson correlation and Euclidean distance measured in 15 potato genotypes.

Where: Chlorophyll Concentration (SPAD), Plant height (HGT; cm), Relative water content (RWC; %), Leaf osmotic potential (LOP; MPa), Leaf dry weight (LDW; g), Stem dry weight (SDW; g), Root dry weight (RDW; g), Tuber dry weight (TDW; g), Tuber number (NTUB; N°), Total transpiration (TRS; mL), Leaf area (LFA; cm²), Root length (RTL; cm), Total dry biomass (TDB; g), Harvest index (HI), Specific leaf area (SLA; cm²g^-1), Relative chlorophyll content (RCC), Biomass water use efficiency (WUE_B; gL^-1), Tuber water use efficiency (WUE_T; gL^-1).

7 Figure 3

Principal Component Analysis (PCA) from variables measured in 15 potato genotypes under well-watered (WW) and water deficit (WD) condition. (A) PCA for the variables. (B) PCA for the genotypes under WW and WD.

Where: Chlorophyll Concentration (SPAD), Plant height (HGT; cm), Relative water content (RWC; %), Leaf osmotic potential (LOP; MPa), Leaf dry weight (LDW; g), Stem dry weight (SDW; g), Root dry weight (RDW; g), Tuber dry weight (TDW; g), Tuber number (NTUB; N°), Total transpiration (TRS; mL), Leaf area (LFA; cm²), Root length (RTL; cm), Total dry biomass (TDB; g), Harvest index (HI), Specific leaf area (SLA; cm²g^-1), Relative chlorophyll content (RCC), Biomass water use efficiency (WUE_B; gL^-1), Tuber water use efficiency (WUE_T; gL^-1).

8 Table S1

Genetic variance (V.g), Error variance (V.e), and repeatability in 15 potatoes genotypes.
Trait	mean	std	min	max	V.g	V.e	repeatability
Chlorophyll concentration (SPAD) at 29 dap	56.36	4.14	46.93	61.96	16.20	9.19	0.88
Chlorophyll concentration (SPAD) at 59 dap	46.84	3.32	40.88	52.97	10.40	6.00	0.87
Chlorophyll concentration (SPAD) at 76 dap	43.88	3.60	39.03	52.10	11.43	15.04	0.75
Chlorophyll concentration (SPAD) at 83 dap	42.02	3.66	37.14	50.59	11.57	17.60	0.72
Plant height (cm)	141.19	13.62	111.40	161.30	169.19	163.20	0.81
Relative water content (%)	63.46	2.73	58.67	70.53	1.19	62.53	0.07
Leaf osmotic potential (MPa)	-2.55	0.10	-2.69	-2.39	0.00	0.17	0.00
Leaf dry weight (g)	14.62	4.17	3.42	20.03	16.00	14.12	0.82
Stem dry weight (g)	12.60	4.75	2.82	22.30	19.96	9.41	0.89
Root dry weight (g)	3.54	1.76	0.82	6.45	3.02	0.63	0.95
Tuber dry weight (g)	31.66	12.18	11.63	53.15	131.65	168.57	0.76
Tuber number (N°)	12.04	3.43	6.00	17.40	9.55	21.90	0.64
Total transpiration (mL)	6.18	1.39	2.77	8.37	1.49	4.53	0.57
Leaf area (cm²)	4938.49	1467.31	1027.44	7072.80	1431807.63	7188488.76	0.44
Root length (cm)	32.85	4.72	24.60	39.50	20.57	16.60	0.83
Total dry biomass (g)	62.74	15.58	26.42	87.80	209.08	341.65	0.71
Harvest index (HI)	0.50	0.14	0.18	0.72	0.02	0.00	0.96
Specific leaf area (cm²g^-1)	319.39	43.38	256.34	410.06	115.92	14981.60	0.03
Relative chlorophyll content (RCC)	0.01	0.01	0.01	0.04	0.00	0.00	0.80
Biomass water use efficiency (gL^-1)	10.35	0.92	9.21	12.12	0.64	1.54	0.62
Tuber water use efficiency (gL^-1)	5.19	1.70	1.81	7.95	2.83	0.73	0.94

9 Figure S1

(A) Fraction of transpirable soil water (FTSW). (B) Daily transpiration in 15 potato genotypes under well-watered (WW) and water deficit (WD) condition.

10 Figure S2

Principal Component Analysis (PCA). (A) Percentage of the explained variance for each dimension. (B) Variance contribution of the first 10 variables in the dimension 1. (C) Variance contribution of the first 10 variables in the dimension 2. (D) Correlation between the studied variables and among the first 5 dimensions. The reference dashed lines on the bar plot corresponds to the expected value if the contribution between the variables where uniform.

11 Figure S3

Tuber yield performance from two contrasting potatoes genotypes. Genotype CIP 398203.244 with good performance under well-watered (WW) with reduced yields during water deficit (WD) condition. Genotype CIP 398190.89 with good response under well-watered (WW) and water deficit (WD) treatment. Each group represent one replication (n = 5). Pictures were taken using the 5 cm scale (black/white segment = 1 cm) displayed alongside the tubers.